


It's all Undyne's fault

by Reading_Wanderer



Category: Undertale
Genre: Anxiety, Humor, It's cultural, Meantions dust (aka death/corpses), Papyrus isn't abusive, Sans still wears a collar, Sleep Deprivation, Swearing, Underfell typical violence, Undyne is still captain of the royal guard, canibalism, it's part of another story idea that may never see light of day, many random deviations from norms are not explained, mentions of canibalism, playing with caps lock
Language: English
Status: In-Progress
Published: 2017-04-23
Updated: 2018-07-14
Packaged: 2018-10-22 21:02:14
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 9,552
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10705029
Author URL: https://archiveofourown.org/users/Reading_Wanderer/pseuds/Reading_Wanderer
Summary: Sometimes, it's just better to stay in bed and ignore the demented bass breaking into your house.Undyne asks the skeleton brothers for help with something. It doesn't go well.





	1. Rude Awakening

**Author's Note:**

> This story is mostly for me to try out the AO3 system and see if I really want to try posting what I write. I may continue this or I may not.
> 
> I don't actually have a good headcannon for UF!Undyne's personality, so ~sleep deprivation~ so I can change her personality later if I want to
> 
> Important thing to note: this Sans mainly uses purple magic and Papyrus' is mainly yellow. They can 'shift' their colors to Blue(Indigo) and Orange respectively. It's part of a larger thought I had about red magic, but that particular idea doesn't really get explained in this.

 

  
Ordinarily, Papyrus considered himself a fairly easygoing guy. Sure his job involved putting the fear of Asgore into the souls of the monsters of Snowdin, but his Dustings tended to be perfectly fair and well deserved. In fact, out of all the Royal Guards, most monsters preferred to be interrogated by the Great Papyrus or, when he was particularly busy, the not-as-great Sans. However, there was a limit to his good nature. Being rudely awoken an hour into his weekly six hour nap to the front door shattering into pieces and a certain one-eyed fish yelling "GUYS HOLY FUCK" was well past that point.

It was in this situation, that Papyrus found himself in that morning. He watched with narrowed eyes as a haphazardly dressed Undyne frantically pinned maps and figures to the kitchen wall with her spears. Having seen her do this several times before to both her own house and even Asgore's kitchen, he made no move to stop her continued destruction of his home. Instead, he kept himself seated rigidly at the kitchen table with his hands wrapped tightly around a cup of warm brown liquid that Sans had passed his way. Of course, if he was imagining the cup to be a certain fish's neck, well that was no one's business but his own.

Sans, on the other hand, was watching the two of them wearily from his own perch on the counter. The second chair from the table having been destroyed in the initial panic fueled skirmish that had occurred directly after their sudden awakening. Neither brother was dressed for company that morning, but Sans was feeling particularly vulnerable as the long shirt he wore to bed kept trying to creep up his legs. The tag on his favorite collar clicked lightly against his clavicle as he attempted to adjust his shirt. The usual comforting friction felt constricting in his anxious state, but he knew better than to go anywhere without one on.

"Alright!" Undyne shouted as she finished pinning up the last of her papers, "Are you ready!" Sans stared miserably, knowing that the best thing to do would to just wait. Papyrus looked at her in confusion and no slight amount of ire as she posed dramatically in front of the destroyed wall. The shadows under her eyes only seemed to emphasize the twitch in her manic stare.

...

Wind blew in from the front door.

...

"READY FOR WHAT?" Papyrus finally snapped when she just stared at them for several minutes, "ALL YOU'VE DONE SO FAR IS BREAK INTO OUR HOUSE AND DESTROY OUR PROPERTY."

“Dude! We've been talking about it for week! The raid, man! The Raid!” The skeleton brothers perked up a bit at the news.

“you found the dust eaters?”

“Nope!” She shouted, posing dramatically once more, “Alphys did. That big Nerd saw them gathering and called me.” Papyrus stared at her dully for an moment while Sans attempted to muffle his chuckles over the mental image of the neurotic lizard attempting to call her crush.

“AND HOW LONG AGO WAS THIS?” Papyrus questioned. He could feel his own eye start to twitch as some of his observations started slotting together. Undyne paused a moment and stared into space.

“What’s today?”

“’bout wednesday,” Sans said, his face deliberately blank save for the twitching of his ever present grin.

“Two days ago then! We’ve been planning ever since. Dude! I am so hyped!” Sans and Papyrus shared a look.

“ALRIGHT," Papyrus sighed, massaging his skull in an effort to dispel the ache that had made its home there, "SANS AND I WILL GO PREPARE. WHO ELSE ARE YOU BRINGING?”

“Uh, No one.” Papyrus stared at her. He was seriously considering throwing her out the door and going back to bed, Dust Eaters or not. He took a deep breath, holding it for a moment before he spoke again.

"THE MOST NOTORIOUS GANG IN THE UNDERGROUND, THE CURRENT BIGGEST THREAT TO ANY MONSTER UNDER LV 6, AND YOU ONLY WANT TO BRING TWO PEOPLE WITH YOU."

"Yep! Me and Alphys were talking, and it turns out that you guys are the only ones we she can guarantee aren't secretly in the gang!" Sans, seeing his brother's hands flexing ominously and the red glow starting up in his sockets, jumped off the counter and placed himself between Papyrus and Undyne.

“well, me and boss are going to get ready," he grinned. His hands automatically went to hide in his pockets and twitched awkwardly as they encountered nothing but air, "why don't you go on ahead and stake out the place?” Undyne's eye narrowed at him.

“Don’t be trying to order me around pipsqueak,” she growled playfully before turning and walking out of the house. Purple and Orange bones sprung up in front of the empty doorway as soon as she was gone. Sans slumped slightly, tension draining from his bones now that she was gone.

Papyrus sighed and stood from the table. “Get Ready Sans, Before She Comes Back.”

“you got it boss,” Sans answered with a smirk before turning himself purple and 'jumping' to the purple node he had permanently anchored to his room.

“REALLY SANS? ARE YOU THAT LAZY?” He complained, stomping up the stairs after him. Familiar chuckles were his only answer. The house was quiet again for a bit, as each brother got ready for the upcoming fight.

“hey Boss?” Sans called suddenly from his room, breaking the silence as a thought occurred to him, “did she ever say where it was?” Papyrus groaned.

\---

Three phone calls and a minor squabble later found the two skeleton brothers trekking through Waterfall. 

Their footsteps were as quiet as possible as they made their way through the unfamiliar territory. Dark clothing and a thin layer of ash over white bone helped them blend into the shadows of Waterfall's side tunnels. Despite the relative safety of the main roads through the kingdom, not even the strongest of monsters dared bring attention to themselves in the back alleys this late at night. The only sounds they made were the sounds of their feet on sodden ground and the soft click of the tag on Sans' collar- a darker one covered in a thin layer of Dust- hitting his zipper with every step. Every so often, small purple bones would pop into being and bury themselves into the ground, glowing brightly for a moment before dimming to match the glow of their surroundings.

The farther they went, fewer and fewer houses could be found dotting the landscape. Soon enough, the caves they were traveling through became too small or too damp for any houses at all. Papyrus grumbled angrily as water dripped down his head and in into his armor where it pooled oddly in his ribs along with the ash from his unprotected skull.

Sans flinched as a loud noise suddenly broke the quiet of the night. It sounded like a sort of rumbling groan, echoing oddly through the damp cave air. The brothers stopped in their tracks and shared a look. Papyrus gathered magic his his gloved hands and stalked forward. Sans followed behind quickly, watching for any attacks from the back. He was so absorbed in his task that he couldn't help but give an 'oof' of surprise when he ran into his brother's immobile frame.

"OH MY GOD UNDYNE!" Sans peered around his brother in confusion only to start chuckling madly at the sight before them. She was standing in the middle of the cave in full royal guard armor, sleeping. Another warbling groan echoed through the cave as she snored. Papyrus growled and stomped towards her, a bone construct forming in his hand. Sans moved over to the side of the cave, fully prepared to jump to his last node should Undyne's awakening prove to be as violent as their own.

"WAKE UP," he shouted, poking her with his conjured femur. If his volume failed to wake her, then surely she'd sense the innate danger and snap to attention!

Undyne snored slightly louder.

"FOR FUCK'S SAKE!" Papyrus stomped his foot and jabbed her again, harder this time. She didn't even twitch despite the front of her armor coming out of the interaction with a new, sizable dent. Papyrus let out a loud growl, grabbed the fish monster by the shoulder plates, and started shaking her rapidly back and forth. "WAKE UP YOU DEMENTED BASS! I DID NOT GET WOKEN UP AT ONE IN THE MORNING AND MARCH ALL THE WAY TO THIS LEAKY ASS CAVE IN WATERFALL JUST TO WATCH YOU SLEEP," he ranted as his brother laughed his metaphorical ass off in the corner. Undyne groaned.

"SHUT UP AND HELP ME SANS!"

"nah, it looks pike you have this covered," he called between chuckles. Papyrus gave a screech and threw his hands up in exasperation, releasing the sleeping fish from his grasp. She fell to the ground with a clatter.

"What the Fuck," she groaned flipping onto her back.

"OH! NOW YOU WAKE UP! WHY THE FUCK WERE YOU SLEEPING IN THE FIRST PLACE!"

"Give me a break man," Undyne moaned, pulling her helmet off and rubbing at her good eye. Papyrus' eyes flashed red for a moment, his bones rattling ominously.

"SO," Sans exclaimed suddenly, jumping in between the two, "how 'bout those dust eaters." Papyrus huffed, crossing his arms and surveying the area. He hadn't almost lost his temper! Of course not; he'd just been shaking ash out from in between his joints.

Undyne yawned. "What time is it?"

" a-trout 3 in the morning." She groaned, pulling herself up from the ground.

"Really dude? Whatever, we have like an hour and a half before they're suppose to meet up. We need *yawn* to find a spot to ambush them from."

"WELL THEY DEFINITELY KNOW WHAT THEY'RE DOING," Papyrus admitted grumpily, "THERE ARE FIVE DIFFERENT ENTRANCES TO THIS AREA ALONE. HOWEVER... SANS!"

"yeah boss?"

"SEE IF THERE ARE ANY LEDGES WE CAN USE TO SPY FROM ABOVE. UNDYNE AND I WILL CHECK OUT THE OTHER TUNNELS." Sans nodded, looking up at the ceiling of their current cavern. It was much higher up than the tunnels they had used to get there. It had to be three or four times higher at least- plenty of room for a ledge or two to have formed. If not naturally, well- he had his ways.

Once the other two had moved into the tunnels, Sans allowed his magic to flair. In a flash of Indigo magic, a group of serpentine skulls answered his call. Several small ones about as long as his forearm immediately swarmed him, nuzzling at his coat and chirping happily. He grinned, scratched their chins affectionately, and looked over the others that floated around. The rest of them were much larger, ranging from several the size of a medium dog to one three times his own size. The largest one floated closer and nudged his skull softly.

"yeah yeah," he murmured leaning into the rough bone for a moment before returning to the task at hand. With the flick of his wrist, the others went shooting upon into the air, searching for a hiding spot. The largest one gave a whine and nibbled softly on his coat a moment before lowering itself all the way onto the floor. He scrambled on top of it, ignoring the huff it gave when he lost his grip for a moment and almost fell back off. 

"come on buddy," he muttered, patting the bone in front of him.

\----

Papyrus moved silently through his chosen tunnel.

Squelch

Squelch

Squelch

Okay, he could admit to himself that he wasn't being totally silent, but moved as silently as a terrestrial monster could in the muddy caves of waterfall. Besides the sounds of his shoes sinking into the mud, he was totally silent.

He looked around carefully as he went, searching for any sign of some kind of supply stash or even some of the gang members, but the tunnel was totally quiet and uninhabited save for the small fireflies and glowing mushrooms native to waterfall. After ten minutes of marching through the mud, the tunnel came to an abrupt end at a small pool of water. Papyrus stopped and yawned. "Fucking fish," he grumbled resisting the urge to rub at his eye sockets and mess up his camouflage.

He contemplated putting a bone trap down at the edge of the pond- perhaps the time it took to pull themselves out of the water would allow them to be harmed by his orange attacks?- before deciding against it. He may have better stamina and control than Sans, but he didn't have nearly as much spare magic to use on plans that might not even work. No, better to hold onto the extra magic for when Undyne inevitably got them into a fight with the Dust Eaters. Looking around one last time, he sighed and went back the way he came.

By the time Papyrus made it back to the convergence point, Undyne was already back to snoring on the ground while a multitude of small blasters bounced through the air chittering and chasing each other with the sort of glee Papyrus had only ever seen in these baby blasters. Several of them raced straight for him, chirping and nuzzling at his clothes. He sighed fondly at them, scratching their heads and shooing them away.

Sans barely looked up from directing the small horde to wave to his brother from his seat several feet in the air, atop the giant one. Papyrus couldn't help but lean back to watch his brother at work. Under Sans' direction, small blasters were pointed at different parts of the wall and directed to shoot their twin beams of almost-magic at the hard stone before being let go back into the swarm until they were chosen again.

The small ones didn't do much damage, but they were much quieter and safer to use on the wet and potentially thin walls in Waterfall. Such a task was likely frustratingly slow, but Sans' perseverance was paying off and already a platform was coming into being in the wall in front of him. Papyrus leaned into the wall next to him and watched his brother work. He blinked slowly, promising himself that he'd go back to searching the area in a moment. Just... another... moment...

 


	2. Smol Cat

**Summary for the Chapter:**

> The Dust Eaters show up!
> 
> ...Undyne sleeps some more.

**Notes for the Chapter:**

> So I had his chapter started when I put up the first one and then life, rewrites, and procrastination happened. I’m going into winter break, so I expect to have a bit more time on my hands for writing for the next month or so.  
> There was one scene in here that I rewrote like 4 times. I think it’s okay now, but feedback is always welcome.  
> TW for anxiety, mentions of death, slight self harm? (Better safe than sorry)  
> -if anyone needs anything tagged, pls tell me-

            Papyrus was really getting tired of being woken up by shouting. He stayed leaning against the wall and, for a moment, seriously considered the pros and cons of killing the captain of the Royal guard. With a sigh, he came to the conclusion that it'd be more work then he cared to put into the endeavor and dragged his eyes back open once more.

            Thankfully, they weren't under attack by hostile forces. On the other hand, Sans and Undyne fighting was not the biggest morale booster. At least Sans seemed to have everything under control, staring, unimpressed, down at a struggling, swearing Undyne. 

            Papyrus wondered, exasperated, what she'd done to provoke Sans. The blasters too, he noticed. He could practically taste the indigo magic in the air as the serpentine skulls bounced in and out of being around them. The one Sans had been riding earlier was sitting on the ground behind him, staring Undyne down while it's fangs glow brightly with charging magic.

            With an almost inaudible groan, Papyrus stood up from where he had been sitting, bones popping back into place with uncomfortably audible popping noises. "WHAT IS GOING ON?" He growled, stalking forward.

            "That little _Shit_ pulled my hair," Undyne growled, managing to get her arms under her and pushing up a bit before crashing to the ground once more.

            "it's your own damn fault for sleeping on the ground," Sans growled back. Now that he was closer, Papyrus could see the small blaster hovering behind his brother's shoulder. His shoulders slumped and he suppressed the urge to groan. Even compared to the next smallest blaster, this one was tiny- it was barely the size of Sans' hand- and his brother doted on it like it was his own babybones.

            "Oh Yeah Shrimp!?! You can't pin me forever! Just wait-"

            "oh please," Sans snapped back, rolling the pips of his eyes, "pinning you so easy, a babybones could do it."

            "NNNNNGGGGGGGHHHHHHHHAAAAAA!!!!!" Undyne shouted, actually managing to lift herself up off the ground. Sans' eye pips shrank a bit in surprise as a bead of condensed magic formed on his skull.

            "THAT'S ENOUGH BOTH OF YOU," Papyrus growled, pushing Sans away from the irate fish and placing himself between them, "WE CAME HERE FOR A REASON. NOW STOP YOUR PETTY SQUABBLING AND LET US GET THIS OVER WITH ALREADY."

            "hey, at least I got my job done," Sans muttered back petulantly, hoisting himself up onto his blaster once more. Papyrus winced and inspected the incredibly interesting architecture of the wall. Undyne glared and spit on the floor in Sans' direction. Sans glared back and sent Undyne flying into the wall. She let out a grunt at the impact before sliding down as the last of the indigo magic holding her dissipated. 

            "UNDYNE..." Papyrus warned, glaring at her as well. She rolled her eyes.

            "Whatever," she growled, rising from the ground with a wince. She let out a loud yawn and shook off  the dust clinging to. Then, she ran over to wall underneath Sans' platform, jumped onto the wall, and used the claws of her gauntlets to climb up the rest of the way to the ledge. Papyrus sighed and let it go. He was too tired for this shit. 

            Then he looked up. 

            "Fuckers," he muttered under his breath. So much for saving up all of his magic. With yet another sigh and a snap of his fingers, he summoned a platform of interlocking bones, stepped on them, and rode the platform up to the ledge.

            Sans was standing over where the wall met the floor when Papyrus got there, his posture stuff as his hands fidgeted with whatever dust and debris had gotten on them. Papyrus could practically feel Sans fretting as he beckoned blasters closer and had them shoot increasingly small and inconsequential patches for reasons unknown to anyone else. Papyrus sighed. He had wondered, once or twice while they were younger, if his brother would ever get over his various anxieties, but time and experience continued to point towards 'no'. He moved over to his brother's side, hooked his fingers around Sans' collar, and tugged at it almost absentmindedly as he looked over his brother's work. It looked good to him, the edges weren't smooth or ragged enough to really catch attention and the angle at which the wall was cut away to even allow a platform to exist was not too large or out of place.

             "IT LOOKS ACCEPTABLE," Papyrus commented finally. He could feel Sans lean back into his hand and sigh as his previous tension seemed to leave him all at once. Papyrus could feel his own tension release as well. He could never be completely sure how much assurance his brother would need. Too much and he took it as patronizing. Too little and he continued to fret. It was always a relief when he managed to accurately respond to the situation.

            The two stood there a moment before Sans stepped away to deal with the blasters still dancing through the air below. Papyrus let his fingers slip out from around the collar easily and moved over to where Undyne was perched, staring blankly at the lower floor. There was no one there besides a couple blasters that popped out of existence all at once with a flare of Indigo magic as Sans sent them away.

            "HOW MUCH LONGER DO WE HAVE?" Papyrus questioned as he crouched down next to her. His eyes flit around the area, taking in and memorizing as much of the terrain as he could. He could hear Sans puttering around behind them, likely looking for a spot to nap and pad his HP in preparation for what was coming.

            "Not long," she yawned back, shaking herself out of whatever daze she had fallen into, "we have maybe twenty minutes before this thing's set to start." Papyrus hummed idly, glancing at her for a moment before returning his gaze to the floor below. It was quiet. Save for the ever present sound of rushing water and the whistling of wind currents through the caves, there was nothing. 

\---

            Time slowly crept towards the designated time and then passed it without any sign of their quarry. Papyrus found himself gritting his teeth and fighting back a yawn. The half hour or so nap he had managed had helped, but the monotony of the stakeout was threatening to lull him to sleep. Undyne had already lost that particular battle. 

            Again.

            ...At least this time she wasn't snoring.

            It helped that he could hear his brother sleeping behind him. Air whistled softly between Sans' teeth as his body seemed to forget that breathing was unnecessary. Every so often the sleeping skeleton would stir and move around, quieting down for a minute or two before he started breathing once more. It was a comforting reminder of Sans' trust and cemented Papyrus's resolve to stay awake. The collar was a nice visual reminder, but there was something about seeing the effect his presence could have on his brother's piece of mind that made his chest swell with pride and a renewed sense of purpose. 

            _That_ was the reason he had joined the royal guard. Not the promise of LV or money or even the high social standing. No- Papyrus wanted justice for the generations of monsters that had been terrorized over the years by not only the humans, but their own kind as well. He wanted to create an Underground where even the lowest HP monster could rest easy. His brother being able to sleep soundly wherever he wished was a reward in its own right.

            ... Even if Sans kept drifting off at his sentry station.

\---

             It was almost twenty minutes after the designated time when the sound of feet on rock pulled Papyrus from his resting state. Light from the main caverns had started to filter in, lighting up the area slightly, so he shifted as silently as possible, ignoring the way Undyne continued to sit slumped over in her armor, into a less visible position and waited. Soon enough, a small, darkly colored monster came into view. Between their coloring and the poor lighting, he couldn't pin point their exact typing, but, based on the way the monster below seemed to examine every entrance and their timing, he assumed it was one of the more sharp eyed races. Perhaps one of the rare bird-hybrid types or, more likely, a feline of some kind. 

            They were lucky. Papyrus could think of several different types of monster that would have already found them. Had it been a bat or even a rabbit with their hearing-  He cut off that train of thought quickly, ignoring the way it still rattled along in the back of his mind. 'There Is No Reason To Dwell On What Ifs,' he reminded himself.

            Despite Papyrus's fretting, the scout didn't appear to notice the royal guards sitting just above them. They moved slowly around the cavern floor, checking every entrance. Papyrus started intently when they lingered the two caverns he and Undyne had walked through earlier and the spots where they had fallen asleep. Seeing as the floor in the area was stone, there was no real way for the scout to know that the two had been there- not unless the monster was using something other than sight to pinpoint the spots. 

            Scent probably, Papyrus decided, watching their movements carefully. It gave more credence to the idea that it was a feline, birds, even hybrids, never had a very strong sense of smell. 

            The scout circled the area once, twice before going to stand in the center of the room. Papyrus could feel magic gathering in the air and had to suppress his own instinctual response. His magic repeatedly rose up and pushed against his will before retreating a moment and repeating the process in an attempt to flair out and intimidate the perceived foe. Each time it tried to break from him, he gathered it close. The air around him buzzed, but the scout below wouldn't be able to perceive it.

            The monster's magic seemed to continue to build for an unusually long time. Just as Papyrus was prepared to unleash the burning ball of magic humming across his soul, - stealth be damned, he wasn't going to risk some random threat unleashing a special attack and hitting his brother- wobbly balls of orange magic burst into being around them and bounced erratically out towards the edges of the room.

            'Shit.' Papyrus stared blankly down at the feline below. Their magic had, before disappearing upon reaching the walls, illuminated the room bright enough for him to finally get a good look at the _child_ below.

            The first thing that Papyrus noticed was not their fur, their small stature, their lack of any kind of collar, or even the stripes that ran across their gray shirt. 

            No, the first thing Papyrus noticed was the way their magic seemed to waffle between going where it was being directed and going literally anywhere else. 

            Sure, there were pleanty of monsters who wore stripes as a way of fooling potential opponents, but there was no mistaking or mimicking the way a child's magic wavered as it flew through the air. The _Kitten_ 's bullets weren't even fully defined yet for Fucks Sake, bouncing between unidentifiable blobs and something that looked like it might be a ball of yarn if he squinted and turned his head a little. 

            Not for the first time that morning, Papyrus wished that he'd just thrown Undyne out of the house when he'd had the chance. He took a deep breath and suppressed the urge to check their stats. (They were a _Child_. How was he going to fight a fucking child??? Children were meant to be _Protected_.) He couldn't chance catching their attention, not if there was even the slightest chance that it would bring the wrath of the Dust Eaters down on his sleeping brother. It didn't matter that he was getting cold feet, Sans' safety came first.

            Ignorant to the inner turmoil they had unleashed upon the skeleton hiding above, the scout (the _Child_ ) did one last circuit around the room. Seemingly satisfied that there were no enemies hiding in darkened corners, the feline formed a few more bullets that floated in strategic positions around the room and well above most monster's height. These ones were shaped like mice - in an abstract sort of way. Despite their odd shape, the bullets glowed with a brilliant white light that illuminated all of the lower floor and part of the walls. 

            Papyrus flinched back as the suddenly bright light burned into his eye sockets. The two monsters froze almost in unison as his sudden movement sent rock dust falling to the ground. Papyrus watched as the cat's ears swiveled back and forth in an attempt to figure out the source of the sound. He was frozen in place, his magic buzzing across his bones in indecision. Undyne's breathing seemed all too loud as seconds stretched. Sans was mercifully quiet.  

            Finally, the cat moved back towards the entrance they had come in through. They were still tense, and their ears continued to twitch towards every sound. They paused one last time, looking across the room, but, almost pointedly, never looking up, before turning and leaving the area.

\----

            Sans only barely managed to suppress a flinch upon waking. One moment he had been drifting in a, somewhat physically uncomfortable but still HP padding, nap and the next he found himself staring at his brother's tense frame as familiar magic buzzed in the air around them. He could tell that it wasn’t quite an attack yet, but Papyrus was just on the cusp.

             Sans froze in place. He couldn't see what was happening, but he wasn't willing to move and possibly bring attention to their position if they hadn't been noticed yet. Instead, he watched his brother's back, eyes flicking over to where Undyne was sitting every so often. She was sleeping, again, slumped over in her armor and dead to the world. At least she wasn't snoring this time. Sans made a mental note to _rib_  her about it later, especially considering how pissed she got when he fell asleep on the job.

            ...At least when he fell asleep at his post, he wasn't waiting for a fucking _gang_ to show up. Sans squashed the tiny voice trying to point out that _he_ had been doing the same thing just- Shit!

            Sans forced himself to stay still where he was even as the light from an Orange attack danced on the walls. He could feel his own magic attempting to react to the threat and he let it. Because of course his magic couldn't be fucking useful and start forming a bullet or, hell, even attempt to call one of his pre made bullets from the various stashes he had scattered across the underground. No, his magic had to react by condensing in thick, syrup like drops on the back of his skull. 'so fucking useless,' he grumbled internally, 'stupid. stupid. stupid.'

            Sans grit his teeth and forced himself to focus on what was happening, but he could only really just stare at his brother's back and wait to see what happened. Papyrus's magic had stopped vibrating the air around them, but Sans let his continue to condense into drops on his head, unsure if the move was an attempt to prevent them from being detected or if it meant that danger had passed.

            Just as Sans was about to bring his arms under him and start getting up, the cavern filled with bright light. Sans froze and watched as his brother, Mr. Always-in-control-perfectionist, made the mistake of flinching back before freezing. He bit down on the urge to teleport to his brother's side, aversion to Indigo based teleportation be damned. His magic vibrated readily across his fingers as he bit back the urge to call the blasters to attack whatever had caught Papyrus off guard. He still didn't know what was happening, but Sans was prepared to protect his brother.

            They stayed in that tableau for what felt like hours, unmoving as the corpses they so resembled. Sans jumped, eyes wide and magic flaring, when his brother suddenly gave a loud sigh and flopped backwards onto the ground. "Pa- Boss!" Sans yelped, darting forward and checking his brother over for injuries. Papyrus fended off the grabbing fingers with an air of exasperated fondness.

            "Enough," he growled, snatching Sans's hands as the grabbing went from endearing to annoying. "I'm Fine Brother." Sans jerked his hands back and growled right back at him.

            "Fine? what the Fuck was that then?! you Flinched." Papyrus sighed, covering his face before launching into an abbreviated version of what he had just seen.    

            "...AND THEN THEY LEFT," Papyrus finished awkwardly, playing with the metal tips of his gloves. Sans couldn't keep an uncomfortable frown off his own face. They knew that the Dust eaters were recruiting children, but that didn't make seeing it, or listening to his brother describe it, any easier. The two sat there a moment longer, mulling over the information.

            "I DON'T LIKE THIS," Papyrus said finally, "CHILDREN ARE MEANT TO BE PROTECTED." Sans nodded in agreement even as he tried to think of something to say to make the upcoming job a bit easier. They couldn't let more monsters with Unstable-LV roam the Underground, not when they had the chance to solve the issue before it became one.

            "why don't you wake up undyne?" Sans said finally. Papyrus grumped a bit, but did turn to where Undyne was napping on the edge of the platform. He pulled off her helmet and, seemingly remembering what happened earlier, grabbed a lock of her hair and gave it a strong tug. Undyne's eye snapped open and she hissed in outrage. Sans jumped at the sound and, before he could really think about it, turned Undyne blue and shoved her off the ledge.

            She hit the ground with a loud thud. "I didn't even do anything that time!" She whined. Papyrus put a hand over his eyes, but Sans could see him suppressing laughter. The minute shaking of his shoulders always gave him away.

            "sorry," Sans called, not bothering to suppress his grin as he peered at her over the edge, "you want me to bring you back up?" She groaned. 

            "...Yeah."      

            ---

            Once Undyne was retrieved, Papyrus quickly went over what he had seen once again.

            "at least we know they're still coming now," Sans said, mulling over the information, "but, something seems off-"

            "Finally!" Undyne grinned, ignoring him. "Time to kick some ass." Papyrus scoffed at her excitement and pulled out a camera from his inventory,

            "PICTURES FIRST UNDYNE," he chided "WE DO NOT NEED ASGORE ON OUR ASSES JUST BECAUSE YOU RAN IN AND DUSTED SOMEONE WITHOUT PROOF. AGAIN."

            "That was one-"

            "FIVE"

            "-five. Really? It's been five times?"

            Sans grinned and started ticking them off one by one, "the time the spider monster fell in the doughnut maker and no one realized until it was too late, that time someone spilled flour just before you passed by and you dropped the ceiling on them, during that funeral in hotland-"

            "Alright, Alright already," Undyne growled, "I get it. We wait for the damn pictures and _then_  we kick some Ass!" Papyrus tossed the camera to his brother. Suddenly, a scraping noise from one of the tunnels caught their attention. The trio sunk back to the ground and edged towards the side of the platform. Sans carefully tucked the tag of his collar into his shirt and pulled the camera forward, already recording. 

            "SHhhh," a gruff voice echoed out from the tunnel, "keep quiet. One the scouts said they saw the cap'in and her pet science experimen's wanderin' 'round here earlier." The only audible response they could hear was an unimpressed snort. The trio shared tense looks.

            "STUPID STUPID STUPID," Papyrus berated himself as his metal tipped gloves dug into his arms, "I NEVER SHOULD HAVE LET MY GUARD DOWN. OF FUCKING COURSE THAT WOULDN'T BE THE ONLY SCOUT THEY HAD. HOW COULD I HAVE-'. A scaled hand on his shoulder made him flinch and snap out of his self recriminations.

            'Keep it together,' Undyne mouthed, lifting her hand, thumping his back quietly, and turning back to the lower floor. Papyrus took a deep breath, letting the air tickle out from between his ribs as he slowly pulled his thoughts together. 

            'What's Done Is Done,' he reminded himself, 'They Don't Know We're Still Here Or They Wouldn't Be Coming. Sans Is Still Safe. I HAVEN'T FAILED.' He couldn't help but take a glance at his brother. Sans was frowning as he continued to film the lower cavern and the echos of monsters congregating in the tunnels beyond, but there were no overt signs of him being unwell physically or mentally. 'Sans is still safe,' he reminded himself once more before returning his attention to the hoard forming below.

**Notes for the Chapter:**

> Thanks for reading. If you want to ask questions about the plot or background or give me some feedback about the chapters, I can be found at https://reading-wanderer.tumblr.com .  
> -Fair warning, most of my blog is going to be random stuff, cats, dnd, and political type things-  
> I’m going to try to be faster about the next one, but no promises.


	3. in which we almost get to the action

By the time the deluge of new monsters coming in from the tunnels slowed to a trickle, Papyrus had managed to count fifty three different monsters of various types- none of which were the scout from before. That’s not to say that there were no cats at all, however.

As to be expected, the majority were species native to Waterfall. The largest group of one species were from clan Aaron. There were three males, five females, seven more that were androgynous and one that seemed to be more scar than monster. There were also at least four leeches, three undines, and the last two members of the Piranha clan that had been decimated a month ago by a cave in. There were about five adult cats of various colors. (If he was the type, Papyrus would bet money on at least one of the cats below being the scout’s parent.) The rest of the monsters were a mix of slimes, birds, a moldybigg, and several different types of bug.

It was stupidly easy for Papyrus to pick out each distinct type of monster as they grouped together into clumps around the cavern. There were only two monster species that _weren’t_ converging into distinct groups: the cats and the Aarons.

The Aarons were probably running the show, Papyrus decided as he watched them move confidently from group to group, chatting and touching each monster they ran into.

Once Sans had started busying himself with filming the monsters coming into the cavern, Papyrus tapped on Undyne’s shoulder and gestured for her to come back farther into the shadows of the wall- they were already pushing it with just Sans peaking over the edge, they didn’t need Undyne’s armor reflecting light back down and getting someone’s attention. “WE NEED A PLAN,” Papyrus signed in Hands, “THERE ARE TOO MANY MONSTERS COMING IN FOR US TO TAKE ON OUR OWN.” Undyne nodded with an angry look.

“We need to capture the leaders at the very least, the king wants a public trial,” she signed back, though the flaring of her fins belayed her displeasure, “I still say we need to dust as many of these potatoes as possible. Sans is getting the evidence-we have the right.” Papyrus’s ever present grin gave a twitch as he tried not to let his amusement show. Undyne still hadn’t caught on to Sans’ prank and Papyrus didn’t feel like being the one to ruin the harmless fun.

“DON’T LET YOUR LV DO THE THINKING FOR YOU,” Papyrus chided instead, “IF NOTHING ELSE, THEY COULD BE USED FOR STUDY IN THE LABS.” Undyne’s fin twitched.

She glared, signing, “Potato you, you high and mighty potato.” She opened her mouth, ready to chew him out before stopping and letting out an aggravated sigh instead. “You know what. Potato it. We can settle that later. How the Potato you planning on catching these potatoes.” Papyrus struggled to keep a straight face.

—xx—

The worst part of manning the camera Sans decided, was trying to figure out where he was suppose to look. With over fifty monsters milling about below, there were a lot of faces to focus on. He could try to get good shots of each face, so they knew who to go after if they escaped, but he would end up missing the interactions between monsters that may help later. If he focused on one group, he would miss the other groups around the cavern. If he tried to view everyone at once, he wouldn’t be able to capture enough detail to identify anyone. ' i hate this job,' he grumbled to himself. Sans glanced back towards his brother and Undyne, biting back the urge to ask them what they wanted him to focus on. They were busy planning, they didn’t need him butting in and asking stupid questions.

"i can do this," he told himself, closing his eyes and taking a deep breath, "it’s not a big deal. boss wont- if I mess up he wont do nuthin'." He opened his eyes once more and focused on the monsters below.

He started with a quick once over of the cavern, counting the monsters as he went. After double and triple checking his numbers, Sans counted fifty seven different monsters. The task was made easier by the way that they clumped into smaller groups. The only ones that were giving him trouble were the cats and the Aarons. The cats seemed to be actively avoiding each other and kept slipping between groups and ducking behind other monsters in order to keep that distance. Sans winced as two of them accidentally ran into each other. None of the other monsters even batted an eye as a the one, a darker gray cat, hissed and struck out at the other, a bright blue cat that was missing chunks out of its ears. Despite the difficulty in finding them, Sans managed to count five cats in all. None of them looked like the cat Papyrus had been describing before. Sans found it a bit odd, but tried not to dwell on it.

The Aaron’s were much easier to track and he counted about sixteen in all. Even though they were spread out among the groups, they didn’t hide behind other monsters the same way. They _trotted_ easily around groups and the other monsters seemed almost welcoming when the Aarons tried to talk to them. It seemed like they were the only ones though. As Sans scanned over the monsters below, he noticed that a lot of them were taking shots at each other, not just the cats. None of them were using magic, but plenty of monsters had claws or spikes of some kind and many of the monsters below were taking advantage of that.

Sans shuttered as he watched a mantis type monster run it’s serrated arm along the back of a nearby beetle and start licking the dust off as if that was something normal that they did all the time. The beetle didn’t just take it either, turning and attempting to ram into the mantis in retaliation. Sans closed his eyes when the mantis easily caught the beetle's horn and brought it up to its mouth.

"shit, fuck, fucking stars damn it," he whimpered. When he finally looked again, the mantis had moved on while the beetle was surrounded by its kin and missing a good chunk off the end of its horn.

Sans gagged. "i'm in hell," he whined softly. He zoomed out and did a once over of the monsters again, trying not to focus on anyone anymore. The Aarons were moving more around the edges of the gang, he noted. They seemed to be herding everyone away from one of the tunnels. Unfortunately, that also meant that the other monsters had to get closer together and Sans found himself gagging again as the closer quarters led to more acts of casual cannibalism. "fucking hell," Sans muttered under his breath, "how the fuck did they manage to get this many people to band together when they’re pulling this shit?" He was honestly surprised that none of them had used magic on each other yet.

Sans took one more close up sweep of the crowd before zooming out even more to watch the gang as a whole. While the others attacked and ate each other like some kind of demented buffet, the Aarons were seemingly completely unaffected. The only other monster not actively participating in the Dust bath was a Moldybigg that none of the others even tried getting close to. Sans couldn’t help but wonder what the Moldybigg had done to get these demented fuckers to give it space. As he was considering it, one of the monsters nearby caught his eye- just in time to see them lose a chunk off their arm. Sans shuttered.

Maybe he was better off not knowing.

“ain’t this _Dust_ the way. should have known we were going _bite_ off more than we could chew,” Sans punned miserably in an attempt to cheer himself up, “no _bones_ about it. this seems like a g _rave_ mistake. just a _cat-_ astrophy in the making. too many _fish_ to fry for us to _horse_ around.” He gave a weak chuckle.

“It’s a good thing there aren’t any ghosts around here or this might _haunt_ me-“

“Are You Punning,” Papyrus mock growled as he hovered over Sans’ shoulder so he could look at the camera screen.

“who? me?”

“No, Undyne,” he huffed as he adjusted Sans’ hands in order to get a better view of the things going on below. Sans gave a more genuine smile and opened his mouth to continue his punning when a loud bang from below suddenly caught their attention.

Sans swung the camera over to film the cavern the Aaron’s had been gradually been _herding_ the other monsters away from. Another bang sounded and then rumbling. The sounds got louder and louder as whatever it was got closer. Sans’ finger tightened on the camera as he swung quickly back over to the assembled monsters to see their responses.

Any division between the different types of monsters were all but gone. If fact, they all pressed into each other, straining to be in the front of the pack where the Aaron’s were keeping monsters back. Sans was somewhat surprised to see that none of them were eating each other anymore. He nudged his brother. “looks like they’re bringing in the main event.”

Finally, a pair of Aaron’s made their way into the cavern, followed closely by a large wooden cart that banged and shuttered as went. The back was covered by a dark, mud covered tarp while a small, dark blue cat monster sat in the driver seat. Sans could feel his brother’s fingers tighten minutely where they still rested on his hands and resisted the urge to check on him.

They watched silently with the churning crowd below as cart pullers un-clipped themselves from the front of the cart and pulled back the wiggling tarp.

 

Fuck. Those were children. And a Woshua.

 

‘Why the Woshua?’ Sans wondered, deliberately not looking at Undyne. He could feel magic condensing on the back of his head again because of her magic charging in the air around them. Shit. He was not looking forward to the lectures on effective use of lethal force again.

Trying not to sigh aloud at the thought, Sans zoomed in on the camera so he could get a better look at the children. Another duo of Arrons had broken off from the barrier between the cart and the crowd and were hauling themselves into the back. Sans watched as they tossed the Woshua onto the front seat with the cat and then passed the children, two at a time, from the back of the wagon to the Aarons on the ground. They were then _herded_ into the space between the wagon and the other Aarons.

There were a lot of them. There had to be over twenty, though Sans wasn’t really interested in counting them at the moment. None of them seemed to have come willingly. Most of them continued to struggle and bite at their captors. It didn’t do them much good though, as they were either hit into compliance or laughed at depending on how much damage they managed to inflict. Sans made sure to get a good shot of each of them as they were moved- it would make finding the parents easier. It wasn’t until he had gone over a few that he finally figured out what had Undyne so riled up.

None of the children were wearing collars or any kind of clan identifying mark. Shit. Sans risked a glance over at Undyne as they pulled the last of the children out of the cart and moved them to the center.

Her eye was narrowed and her form still as she took in the cart below. The quills she usually kept down tucked down in her hair were fully erect- displaying the vibrant red membrane that stretched between them.

Sans looked back down and had to stifle the urge to bail before Undyne jumped down and tried to take them down single-handedly.

\---

Papyrus glared down at the Dust hungry horde below. These _creatures_ had no morals or honor to speak of. Watching over Sans’ shoulder, he could see the children being tossed around like toys. There was even an Aaron child among the group- though they were being kept closer to the cart than the others. Papyrus felt sick when he saw another pair of kittens among the ones being tossed around. Unlike their darker blue counterpart on the cart, they were smaller and more of a pale blue-gray. Through the camera in Sans’ hands, however, Papyrus could see the way that all three of them had the same colored eyes. He could also see the way that the foot on one of the gray ones dangled in an odd direction and the way that the other seemed to react just a bit too slowly to sudden movements.

Papyrus clenched his teeth and watched as Sans looked over the other children. There were several dragons among the group- they seemed to be the most vicious of the children. A silver one even managed to latch onto one of the Aarons with their claws while the Dust Eater was pulling a small frog like monster out from where it had hidden beneath the drakeling’s wing.

Looking over them, Papyrus couldn’t help but feel like they looked familiar somehow. He turned to where Undyne was kneeling and, after nudging her to get her attention, signed “DO YOU KNOW THEM?” She had to know something, he figured, or she wouldn’t be so riled up. Undyne gnashes her teeth a bit, wiggling her cheek fins back and forth as she did it.

“Those are kids from The Cracks.” Papyrus winced. Yeah, fuck—that would do it. Three years of bartering, reassurance, and promises all down the drain. The only reason the orphans had trusted Undyne enough to even speak with them was because she had been one of them once. Undyne’s frill drooped a bit.

“I promised them that things were different, and look what happened. I potato let them down.”

“IT IS NOT YOUR FAULT THAT MONSTERS LIKE THIS EXIST, UNDYNE. THE BEST THING THAT WE CAN DO RIGHT NOW IS TO KEEP THIS FROM HAPPENING EVER AGAIN.” Undyne gave him a sharp, toothy grin.

“Let’s go fuck them up.”

Papyrus gave her his own sharp smile as he pulled himself away from his brother to crouch over the edge of the platform. Seeing the two of them getting ready to jump in like idiots, Sans gave a sigh and put the camera back into his inventory. “i’ll get the kiddos loose, you guys distract the gang members.”

“Those fuckers are going down,” Undyne growled.

-xx—xx-

Sans flitted from Purple node to Purple node, setting up motion traps in the tunnels, just out of sight of the main area. He moved as quickly as he dared, setting up thin purple bones for fleeing monsters to run into. He could hear the gang members cheering and jeering at the Woshua they had picked up. He had only barely managed to get the other two to hold back from jumping in the center of things. Thankfully, the Aarons had turned the Dust hungry monsters’ attentions from the kids to the Woshua before they could.

Apparently the dude had claimed the Aaron kid under the protection of his clan. They made this whole pompous speech and everything about how they didn’t need the AcidBath clan making their children weak. For now, they seemed to be amusing themselves with pushing Woshua around and tossing sweat bullets at him, but Sans was sure that that would change soon enough. Once the last bone had been placed, Sans slowly picked his way towards the mouth of the tunnel, watching and listening intently for any sign of someone seeing him. Seeing the crowd of monsters gathered at the mouth of the tunnel, Sans gave a tense smile. It was all going according to plan. Now to create his last trap and, hopefully, the first distraction.

Pulling himself back out of sight once more, Sans started gathering a ball of purple magic in his hand. Once it got to the size of a tennis ball, he closed his eyes, took a deep breath, and _pulled_ at the magic in the ball. Slowly, the magic shifted from a pure Purple to a pulsing mix of Purple and Indigo. Opening his eyes once more, Sans looked down at the volatile orb with no small amount of pride. Then, tossing the ball a couple times to get a feel for the weight, Sans crept towards the crowd at the end of the tunnel and, once he got too close for his nerves to handle going any further, hurled the ball of magic into the midst of them. As soon as it left his hand, Sans turned himself purple and jumped to the node he had placed in the cave behind the cart.

— —

The ball of magic hit one of the monsters in the crowd with a dull thud before rolling off of them and onto the floor. The monster, a mantis type, hissed and swiped at the monster directly behind them, a swan type. The ball fell to the floor, unseen and ignored.

Dust flew as the Swan and mantis hacked and bashed at each other with their physical weapons. Some of the monsters around them scattered to avoid getting hit by the wildly flailing limbs of the combatants while others jumped into the fray and attacked the original two fighters and each other. The Aarons closest to them shouted and started wading through the crowd towards the brawl. None of the monsters noticed the way the shed dust was being pulled towards the small ball of magic.

— — —

 

Once in the tunnel, Sans ducked into the shadows of the cart and looked up to where his brother and Undyne were sitting. He could barely see them in the darkness at the edge of the light, but he didn’t need to see them; they just needed to see him. Summoning a small, sharp white bone, he bounced it a couple times so that it would catch the light. Then, holding the bone in his hand he inched towards where the kids were scooting towards freedom. Most of them had paused and were watching the fight unfolding between several of the Dust Eaters back where he had thrown his magic orb. The Aarons closer to those monsters were _wading_ through the crowd and attempting to break them up. Sans winced as the Shawn threw a feather shaped bullet at the mantis only to miss and hit the monster behind them- looks like whatever was holding them back earlier wasn’t anymore.

Suddenly, loud yell echoed through the cavern, making him and the children in front of him jump. He grinned as Undyne _dove_ into the crowd and captured the attention of the other Dust Eaters. With them distracted, Sans finally scooted out of the shadows and towards the captured children.

The closest child was one of the Drakelings that had been giving the Aarons the most trouble. As soon as he got close enough to touch them, they turned and attempted to snap at him. Their attempt was somewhat hindered by a length of rope tied around their snout. Sans obligingly backed up a couple inches. Then, glancing meaningfully at the fight going on in the middle of the room, Sans pulled down the edge of his jacket enough to reveal his collar and the Royal Crest on the tag.

The young dragon glared at him, but when he reached for their rope they didn’t snap at him again. He pulled the rope taunt and then snapped it with a slash of the bone bullet. As soon as their arms were free, the dragon reach up and sliced off the rope on their muzzle with an easy slash of their claws.

Once freed, the dragon didn’t give him a second glance. Instead, they immediately set about releasing the others nearest to them. Sans watched for a moment before he scooted towards another of the drakelings and freed them too.

A loud BOOM echoing through the cavern had many of the newly freed children skittering for safety deeper in the tunnel. Sans obligingly lifted his purple bone trap out of their way as they went. The slipped under without a problem and disappeared into the darkness.

A sudden angry shout had Sans snapping to attention and he slammed his trap back into place. He jumped to his feet and summoned a shield of bones just in time for an arm shaped bulled to plow into it. His bones splintered under the force, but managed to block the attack.

The rest of untied children around him bolted for the tunnel save for the pair of drakelings he had untied and a third that they had gotten to. The three dragons instead stood between the charging Aaron and the ones who were still tied up. They flared their wings and spewed fire at the approaching monster.

The Aaron deflected the fire with a couple sweat bullets and continued to stalk forward. Another, familiar yell filled the air.

The Aaron fell to the ground, knocked out, as a pair of sword like bone constructs slashed across their back.

Sans watched him, conflicted. Papyrus was suppose to be keeping an eye on things from above. Sans sighed before turning back to his task. Papyrus would make sure he was safe, Sans just had to make sure he kept one eye on Paps too.

 

**Author's Note:**

> Honest criticism welcome. If I missed a spelling mistake, tell me pls.
> 
> If I don't continue this story:
> 
> "What Do You Mean They Didn't Come!"  
> "they didnt show up. and you two slept through all the inaction."  
> "WHAT A WASTE OF TIME."


End file.
